A 13-year-old girl with a pituitary abscess complained of continuous headache and bitemporal hemianopsia after a common cold. However, she had no inflammatory reactions on admission. Computed tomography showed a low-density sellar mass lesion extending to the suprasellar cistern with a peripheral low-density area, and ring enhancement of the capsule with a particularly thick region. Magnetic resonance imaging showed the mass lesion as a low and high-intensity area on the T₁- and T₂-weighted images, respectively. The iso-intense rim of the lesion and the left frontal mass lesion adjacent to the capsule were enhanced by gadolinium-diethylenetriaminepenta-acetic acid. Magnetic resonance imaging also indicated only mild sphenoidal sinusitis which may be representative of the inflammatory process. Careful assessments of neuroimaging findings and preceding trivial inflammatory signs are necessary for the correct diagnosis of a pituitary abscess.